A projectile is fired from ground with an initial velocity that has a vertical component of 20m/s and a horizontal component of 30m/s. Using g = 10m/s2, the distance from launching to landing points is:
Correct answer: D. 120m
- A. 40m
- B. 80m
- C. 60m
- D. 120m
Explanation
The projectile is launched with a vertical velocity of 20 m/s and a horizontal velocity of 30 m/s. To find the time of flight, we first calculate the time to reach maximum height using the formula t = v/g. Here, v is 20 m/s and g is 10 m/s2, which results in a time to peak of 2 seconds. Therefore, the total time of flight is twice this value, amounting to 4 seconds. Next, we calculate the range using the horizontal velocity: Range = horizontal velocity × total time of flight. This gives us Range = 30 m/s × 4 s = 120 m. Options A and B underestimate the range due to miscalculations regarding time of flight. Option C, while it appears plausible, inaccurately simplifies the relationship between time of flight and horizontal distance, leading to an incorrect conclusion. Therefore, the correct range is found in Option D at 120m.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Force and Motion
Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
Practise Force and Motion
1,416 free Force and Motion MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Force and Motion questions
Which of the curves on the graph below best represents the vertical component "vy" of the velocity versus the time t for a projectile fired at an angle of 45o above the horizontal?
A ball is thrown up with 20 ms-1 at an angle of 60° with x-axis. The horizontal velocity of the ball at the top position is:
Velocity of an object dropped from a building at any instant "t" is given by:
A student's life was saved in an automobile accident because an airbag expanded in front of his head. If the car had not been equipped with an airbag, the windshield would have stopped the motion of his head in a much shorter time. Compared to the windshield, the airbag:
Which of the following velocity-time graph represents infinite acceleration?
A train of length 150 in is going to north with a speed of 10ms-1. A parrot flies 5 ms-1 toward south parallel to the railway line. The time taken by parrot to cross the train is: